1. Field of the Invention
The present invention relates to light-emitting diode (LED) packages and method for fabricating the same, particularly to an LED package having a high light-emitting quality and a method for fabricating the same.
2. Description of Related Art
Light-emitting diodes (LEDs) are widely used in many electronic devices, such as computers, mobile phones, and personal digital assistants (PDAs). In use, LEDs are usually arranged in arrays and assembled with other components to form LED packages to improving their light-emitting quality.
Referring to FIG. 4, a typical LED package 100 includes an LED array 12, a housing 14 and a packaging member 16. The housing 14 is bowl shaped in profile, the LED array 12 is mounted on a central portion of an inner surface (not labeled) of the housing 14. The inner surface is configured to have a predetermined reflectivity, so that light propagating/radiating out of the LED array 12 is reflected and then enhances the light-emitting intensity of the LED package 100. The packaging member 16 includes a packaging layer 161 that is made of transparent materials, such as resin, and many phosphor grains 162 mixed in the packaging layer 161 uniformly and homogeneously. The packaging layer 161 is disposed in the housing 14 to package the LED array 12 and form a flat light exiting surface 1611 adjacent to the opening (not labeled) of the housing 14. In this way, when the LED array 12 is powered and emits primary light, the primary light invokes/activates the phosphor grains 162 to emit secondary light. The secondary light is mixed with the primary light to form final light having a predetermined color and traveling out of the light exiting surface 1611. For example, if the LED array 12 emits primary light blue in color and the phosphor grains 162 emit secondary light yellow in color, the final light would be white light.
However, in the typical LED package 100, because the housing 14 is configured in a bowl shape, distance between the LED array 12 and different points of the light exiting surfaces varies. Therefore, primary light propagating/radiating out of different portions of the light exiting surface 1611 may respectively propagates/radiates in various distances in the packaging layer 161 and activate different numbers of the phosphor grains 162, thus are respectively mixed with different amounts of secondary light and have different colors. In this way, light emitting quality of the LED package 100 is decreased.
For example, as shown in FIG. 4, a distance between the point B of the light exiting surface 1611 and the LED array 12 is less than a distance between the point A or C of the light exiting surface 1611 and the LED array 12. Primary blue light propagating/radiating from the LED array 12 to the point B has a short propagating/radiating distance in the packaging layer 161 and activates less phosphor grains to emit secondary yellow light. Thus, the final light propagating/radiating from the point B is mixed with less secondary yellow light and tends to be blue in color. On the other hand, primary blue light propagating/radiating from the LED array 12 to the point A or the point C has a long propagating/radiating distance in the packaging layer 161 and activates more phosphor grains to emit secondary yellow light, thus the final light propagating/radiating from the point A or the point C has more secondary yellow light mixed therein and tends to be yellow in color. Therefore, final light propagating/radiating out of different portions of the light exiting surface 1611 may propagate/radiate in various distances in the packaging layer 161 and activate different numbers the phosphor grains 162, thus are respectively mixed with different amounts of yellow light and have different colors. Additionally, if the phosphor grains 162 are not enough uniformly and homogenously mixed in the packaging layer 161 in fabrication, the difference in color of final light emitted from different portions of the light exiting surface 1611 may be further increased.
Therefore, a new LED package and a new method for fabricating the same are desired in order to overcome the above-described shortcomings.